The proposed research will continue a systematic investigation of probable in vivo regulatory mechanisms, which control the establishment, maintenance and reversal of enzyme specific latency during cellular aging in the slime mold, Dictyostelium discoideum using trehalase as a model system. The specific aims to be achieved will be: (1) to determine the basis for the increase in trehalase specific activity during germination; (2) to localize intracellular trehalase in the dormant spore by application of the techniques of immunoferritin and/or indirect immunofluorescent staining using purified specific antibody elicited against this enzyme; (3) to determine the basis for the decrease in trehalase specific activity during the aggregation process and (4) to resolve, purify and characterize the multiple forms of trehalase from aging, mature sorocarps and to determine the basis for changes in their specific activity during sorocarp formation.